Update mqttd hal code, can control relay now

Guo Wenxue

2019-06-27 b64d6ff04401ed85fce543b8e20c8c360fb284f5

 apue/2.Socket/socket_client.c

@@ -109,7 +109,8 @@
          }
       }

       //printf("Read %d bytes data from server: '%s'\n", rv, buf);

       sleep(5);
    }